/*******************************************************************************
 * Copyright (c) 2004, 2015 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     John Camelon (IBM) - Initial API and implementation
 *     Markus Schorn (Wind River Systems)
 *     Sergey Prigogin (Google)
 *******************************************************************************/
package org.eclipse.cdt.internal.core.dom.parser.cpp;

import org.eclipse.cdt.core.dom.ast.ASTVisitor;
import org.eclipse.cdt.core.dom.ast.IASTDeclaration;
import org.eclipse.cdt.core.dom.ast.IASTExpression;
import org.eclipse.cdt.core.dom.ast.IASTIfStatement;
import org.eclipse.cdt.core.dom.ast.IASTNode;
import org.eclipse.cdt.core.dom.ast.IASTStatement;
import org.eclipse.cdt.core.dom.ast.IScope;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPASTExpression;
import org.eclipse.cdt.core.dom.ast.cpp.ICPPASTIfStatement;
import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.EvalUtil;
import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.ExecIf;
import org.eclipse.cdt.internal.core.dom.parser.cpp.semantics.ExecSimpleDeclaration;

/**
 * If statement in C++
 */
public class CPPASTIfStatement extends CPPASTAttributeOwner implements ICPPASTIfStatement, ICPPExecutionOwner {
    private IASTExpression condition;
    private IASTStatement thenClause;
    private IASTStatement elseClause;
    private IASTDeclaration condDecl;
    private IScope scope;

    public CPPASTIfStatement() {
	}

	public CPPASTIfStatement(IASTDeclaration condition, IASTStatement thenClause, IASTStatement elseClause) {
		setConditionDeclaration(condition);
		setThenClause(thenClause);
		setElseClause(elseClause);
	}

    public CPPASTIfStatement(IASTExpression condition, IASTStatement thenClause, IASTStatement elseClause) {
		setConditionExpression(condition);
		setThenClause(thenClause);
		setElseClause(elseClause);
	}

    @Override
	public CPPASTIfStatement copy() {
		return copy(CopyStyle.withoutLocations);
	}

	@Override
	public CPPASTIfStatement copy(CopyStyle style) {
		CPPASTIfStatement copy = new CPPASTIfStatement();
		copy.setConditionDeclaration(condDecl == null ? null : condDecl.copy(style));
		copy.setConditionExpression(condition == null ? null : condition.copy(style));
		copy.setThenClause(thenClause == null ? null : thenClause.copy(style));
		copy.setElseClause(elseClause == null ? null : elseClause.copy(style));
		return copy(copy, style);
	}

	@Override
	public IASTExpression getConditionExpression() {
        return condition;
    }

    @Override
	public void setConditionExpression(IASTExpression condition) {
        assertNotFrozen();
        this.condition = condition;
        if (condition != null) {
			condition.setParent(this);
			condition.setPropertyInParent(CONDITION);
			condDecl= null;
		}
    }

    @Override
	public IASTStatement getThenClause() {
        return thenClause;
    }

    @Override
	public void setThenClause(IASTStatement thenClause) {
        assertNotFrozen();
        this.thenClause = thenClause;
        if (thenClause != null) {
			thenClause.setParent(this);
			thenClause.setPropertyInParent(THEN);
		}
    }

    @Override
	public IASTStatement getElseClause() {
        return elseClause;
    }

    @Override
	public void setElseClause(IASTStatement elseClause) {
        assertNotFrozen();
        this.elseClause = elseClause;
        if (elseClause != null) {
			elseClause.setParent(this);
			elseClause.setPropertyInParent(ELSE);
		}
    }

	private static class N {
		final IASTIfStatement fIfStatement;
		N fNext;

		N(IASTIfStatement stmt) {
			fIfStatement = stmt;
		}
	}

    @Override
	public boolean accept(ASTVisitor action) {
    	N stack= null;
    	ICPPASTIfStatement stmt= this;
    	loop: for (;;) {
    		if (action.shouldVisitStatements) {
    			switch (action.visit(stmt)) {
    			case ASTVisitor.PROCESS_ABORT: return false;
    			case ASTVisitor.PROCESS_SKIP:
    				stmt= null;
    				break loop;
    			default: break;
    			}
    		}

    		if (!((CPPASTIfStatement) stmt).acceptByAttributeSpecifiers(action)) return false;

    		IASTNode child = stmt.getConditionExpression();
    		if (child != null && !child.accept(action))
    			return false;
    		child= stmt.getConditionDeclaration();
    		if (child != null && !child.accept(action))
    			return false;
    		child= stmt.getThenClause();
    		if (child != null && !child.accept(action))
    			return false;
    		child= stmt.getElseClause();
    		if (child instanceof ICPPASTIfStatement) {
    			if (action.shouldVisitStatements) {
    				N n= new N(stmt);
    				n.fNext= stack;
    				stack= n;
    			}
    			stmt= (ICPPASTIfStatement) child;
    		} else {
    			if (child != null && !child.accept(action))
    				return false;
    			break loop;
    		}
    	}

    	if (action.shouldVisitStatements) {
    		if (stmt != null && action.leave(stmt) == ASTVisitor.PROCESS_ABORT)
    			return false;
    		while (stack != null) {
    			if (action.leave(stack.fIfStatement) == ASTVisitor.PROCESS_ABORT)
    				return false;
    			stack= stack.fNext;
    		}
    	}
        return true;
    }

	@Override
	public void replace(IASTNode child, IASTNode other) {
		if (thenClause == child) {
			other.setParent(child.getParent());
			other.setPropertyInParent(child.getPropertyInParent());
			thenClause = (IASTStatement) other;
			return;
		} else if (elseClause == child) {
			other.setParent(child.getParent());
			other.setPropertyInParent(child.getPropertyInParent());
			elseClause = (IASTStatement) other;
			return;
		} else if (condition == child || condDecl == child) {
			if (other instanceof IASTExpression) {
				setConditionExpression((IASTExpression) other);
			} else if (other instanceof IASTDeclaration) {
				setConditionDeclaration((IASTDeclaration) other);
			}
			return;
		}
		super.replace(child, other);
	}

    @Override
	public IASTDeclaration getConditionDeclaration() {
        return condDecl;
    }

    @Override
	public void setConditionDeclaration(IASTDeclaration d) {
        assertNotFrozen();
        condDecl = d;
        if (d != null) {
			d.setParent(this);
			d.setPropertyInParent(CONDITION);
			condition= null;
		}
    }

	@Override
	public IScope getScope() {
		if (scope == null)
            scope = new CPPBlockScope(this);
        return scope;
    }

	@Override
	public ICPPExecution getExecution() {
		ICPPASTExpression conditionExpr = (ICPPASTExpression) getConditionExpression();
		ICPPExecutionOwner conditionDecl = (ICPPExecutionOwner) getConditionDeclaration();
		ICPPEvaluation conditionExprEval = conditionExpr != null ? conditionExpr.getEvaluation() : null;
		ExecSimpleDeclaration conditionDeclExec = conditionDecl != null ? (ExecSimpleDeclaration) conditionDecl.getExecution() : null;
		ICPPExecution thenClauseExec = EvalUtil.getExecutionFromStatement(getThenClause());
		ICPPExecution elseClauseExec = getElseClause() != null ? EvalUtil.getExecutionFromStatement(getElseClause()) : null;
		return new ExecIf(conditionExprEval, conditionDeclExec, thenClauseExec, elseClauseExec);
	}
}